HIV Viral Load

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Also known as: HIV Nucleic Acid Amplification Test; HIV NAAT; HIV NAT; HIV PCR; Quantitative Plasma RNA Test; HIV Quantification
Formal name: Human Immunodeficiency Virus RNA, Quantitative
Related tests: CD4 and CD8; HIV Antibody; HIV Proviral DNA; p24 Antigen; HIV Drug Resistance (Genotypic and Phenotypic)

At a Glance

Why Get Tested?

To monitor the status of HIV disease, in conjunction with other laboratory tests and physical disease progression, and to guide therapy

When to Get Tested?

When first diagnosed with HIV, every 2 to 8 weeks after the start of therapy or therapy changes, and every 3 to 4 months during long-term therapy, or as your doctor recommends

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). This test measures the amount (viral load) of HIV nucleic acid (RNA) in the blood. 

When a person is initially infected with HIV, the virus replicates — it produces more and more copies of itself — and moves into the lymph nodes, spleen, and other parts of the body. In the early stages of infection, there may not be any noticeable signs or symptoms of disease or only flu-like symptoms, although the virus is usually present in high amounts. Even when there are no symptoms, the virus continues to replicate and to damage or kill immune cells.

About 3-8 weeks (rarely, up to six months) after initial exposure to the virus, the person's immune system begins to produce HIV antibodies in response to the infection and suppresses the HIV viral load, decreasing it to a low level. Initial symptoms typically resolve, but the infection does not go away.

An HIV infection may simmer quietly for a decade or more, slowly degrading the immune system. Eventually, the immune system is so weakened that the disease begins to affect the body's ability to fight infections and certain cancers. Symptoms of AIDS begin to appear at this stage as the body becomes more susceptible to infections with microorganisms such as tuberculosis and fungi or other diseases such as Kaposi's sarcoma. The person's HIV viral load also begins to increase.

Treatments for AIDS are initiated to suppress the amount of HIV virus present in the blood and limit its ability to replicate, slowing the progression of the disease. If a person with AIDS discontinues treatment or if it loses its efficacy, then the person's HIV viral load again begins to increase.

The HIV RNA test detects HIV virus genetic material and measures how many copies of HIV (viral load) are present in the blood at a particular time. It can track increases and decreases in HIV viral load and, in conjunction with a CD4 count, be used to evaluate disease activity and treatment effectiveness.

 

How is the sample collected for testing?

A blood sample is drawn by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

(Updated 2011 January 10). Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents, Plasma HIV RNA Testing. AIDSinfo On-line information]. Available online through http://aidsinfo.nih.gov. Accessed February 2012.

Hillyard, D. et. al. (2011 November). Human Immunodeficiency Virus – HIV. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/HIV.html?client_ID=LTD through http://www.arupconsult.com. Accessed February 2012.

Bennett, N. (Updated 2011 July 14). Laboratory Assays in HIV Infection. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1995114-overview#showall through http://emedicine.medscape.com. Accessed February 2012.

Osterweil, N. (2012 January 12). Infectivity Rises with Plasma Viral Load. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/756807 through http://www.medscape.com. Accessed February 2012.

(© 1995-2012). Test ID: HIVQR, HIV-1 RNA Quantification with Reflex to HIV-1 Genotypic Drug Resistance Mutation Analysis, Plasma. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online through http://www.mayomedicallaboratories.com. Accessed February 2012.

Lowry, F. (2011 May 7). HIV Viral Load Detectable After Just 2 Days Without Meds. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/743566 through http://www.medscape.com. Accessed February 2012.

Delaney, K.P. et. al. Performance of an alternative laboratory-based algorithm for HIV diagnosis in a high-risk population J Clin Virol (2011), doi:10.1016/j.jcv.2011.09.013.

Masciotra, S. et. al. Evaluation of an alternative HIV diagnostic algorithm using specimens from seroconversion panels and persons with established HIV infections. J Clin Virol (2011), doi:10.1016/j.jcv.2011.09.011.

Wesolowski, L. et. al. Performance of an alternative laboratory-based algorithm for diagnosis of HIV infection utilizing a third generation immunoassay, a rpidrapid HIV-1/HIV-2 differentiation test and a DNA or RNA-based nucleic acid amplification test in persons with established HIV-1 infection and blood donors. J Clin Virol (2011), doi:1016/j.jcv.2011.09.026.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 548-552.

Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pp 609-612.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Janice K. Pinson MT, MBA. Molecular Business Strategies, Birmingham, MI.

Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp. 535-538.

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pp. 487-490.

Bennett, N. and Rose, F. (2008 October 22, Updated). HIV Disease. eMedicine [On-line information]. Available online at http://www.emedicine.com/med/TOPIC24.HTM through http://www.emedicine.com. Accessed on 10/26/08.

Mayo Clinic Staff (2008 August 9). MayoClinic HIV/AIDS. MayoClinic.com [On-line information]. Available online at http://www.mayoclinic.com/health/hiv-aids/DS00005 through http://www.mayoclinic.com. Accessed on 10/30/08.

(2005 November, Revised). Human Immunodeficiency Virus (HIV) Introduction. Merck Manual for Healthcare Professionals [On-line information]. Available online at http://www.merck.com/mmpe/sec14/ch192/ch192a.html?qt=HIV&alt=sh through http://www.merck.com. Accessed on 10/30/08.

(2008 September, Reviewed). Human Immunodeficiency Virus – HIV. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/InfectiousDz/Viruses/HIV.html through http://www.arupconsult.com. Accessed on 10/30/08.

(2006 September 22). Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings. CDC MMWR 55(RR14); 1-17 [On-line information]. Available online at http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5514a1.htm through http://www.cdc.gov. Accessed on 11/1/08.

(2008 September, Updated) HIV and Plasma Viral Load Testing. Familydoctor.org [On-line information]. Available online at http://familydoctor.org/online/famdocen/home/common/sexinfections/hiv/654.html through http://familydoctor.org. Accessed on 11/1/08.

(Updated January 9,2009) AVERT.org. HIV testing. Available online at http://www.avert.org/testing.htm. Accessed February 2009.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER and Bruns DE, eds. 4th ed. St. Louis, Missouri: Elsevier Saunders; 2006, Pp. 1567-1568.

(October 22, 2007) National Institute of Allergy and Infectious Diseases. HIV/AIDS. Available online at http://www3.niaid.nih.gov/topics/HIVAIDS/. Accessed February 2009.

Arup Laboratories. ArupConsult. Human Immunodeficiency Testing in Infants. PDF available for download at http://www.arupconsult.com/Algorithms/HIVInfants.pdf through http://www.arupconsult.com. Accessed February 2009.

Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson RA and Pincus MR, eds. Philadelphia: 2007, Pg. 989.

(Reviewed Oct 7, 2008) AIDS infonet.org. Fact sheet, Viral Load Tests. Available online at http://www.aidsinfonet.org/fact_sheets/view/125 through http://www.aidsinfonet.org. Accessed February 2009.